Powder for dusting patterns in foundries.



- metal is poured into the mold.

-Wllll1 is the UNITED srA'rns PATENT OFFICE.

ERNST BRUHL, OF BERLIN GERMANY. POWDER FUR DUSTING PATTERNS IN FOUNDRIES- Patented Jan. 30, 1906.

1'0 all whom, it 777,114] concern.-

Be it known that I, ERNST BRUHL, chemist, a citizen of Germany, residing at N o. 61 Sebastianstrasse, Berlin, in the Kingdom of Prussia and Empire of Germany, have inyented a new and lmproved'Powder for Dustmg the Patterns in Foundries, of which the following is a specification. 7

My invention relates to an improved powder for dusting the patterns used in making sand molds in foundries.

1 v,The improved powder is a perfect substittute for the lycopodium powde combining the same good qualities of the latter while beingmuch cheaper.

Lycopodium powder is at present used for u dusting the patterns because it willnot absorb Water or any other liquid, because it will not melt even at high temperatures, and, lastly, because it will burn away completely Without leaving a residue when the molten The powder subject of the present invention has the samegood qualities as lycopodium powder, while being cheaper.

My improved powder is obtained by filling the pores of a very porous material, such as charcoal or silicious marl, witha resin, such as .sandarac, copal, shellac, acarold resn1,or' 011. This may be done by first dissolving the resin in some solvent, then. saturating the porous material withthe solution, and thereafter evaporatmg'the solvent, or the resin may be melted and mixed with theporous material and the whole ground to powder after it has become cold'and hard. I have found the following process very advantageous in the manufacture of my improved powder: The porous material, such as sili- ;c1o'us marl, and the hard resin, such as sandame, are mixed dry and then gradually heated to a temperature of from 300 to 570 Fahrenheit. The resin will first become soft and will finally melt. As it is gradually absorbed by the porous material the whole mixture ac quires a doughy cheesy consistency and will remain so and will not become liquefied even if the temperature be raised. When the mixture has reached this stage, the resin is almost entirely absorbed in the pores of the. porous material. While the resin is being thus heatresin undergoes a change which becomes a ed, together with the porous material, the

parent by its being harder and-more britt e after getting. cold. Moreover, the resin loses its adhesiveness, which is a very disagreeable property, especially for pattern powders. By

this change the resin loses from ten to twenty per centum of its weight, partly owing to the evaporation of its water content and partly owing to the gases developed and driven off by chemical changes which it undergoes. The proportions of the porous material resin used will vary according to the capacity of the porous material to absorb the resinous substance. It is very important that resin should not remain free in the mixture in any and .the i considerable quantity, as it would melt when heated and stop up the pores of the mold. On 1 the other hand, the amount of porous mate-' rial used should not be too great, as otherwise the powder finally obtained would be too porous. As a rule, up to twenty per centum of the resin may be taken for silicious marl and up to fifty per centum of the resin may be taken for charcoal. The caked substance obtained by the above process has a homogeneous fracture after it has become cool and has entirely lost the )roperties of a mixture, such as would be 0 tamed by melting resin with a non-porous material. The caked substance may be reduced to powder by any suitable means or method. It will be found that the powder may be ground as finely as may be required and will not clog or stick to the pestle or mortar, as would be the case with resin or resin mixtures.

A little sulfur may be added to the resin, which will increase the hardening thereof when heated. Dinitronaphthalene in larger orsmaller quantities or as a solvent may be used. When charcoal is used as the circus material in mixing my improved powr er, the dinitronaphthalene will also serve as coloring material.

When charcoal is used in making my improved powder, as hereinbefore described, the resulting powder is dark in color and w ll burn away completely. Silicious marl will make a powder which is lighter in color, but

will leave a residue when burned, but as this residue consists of silicic anhydrid, which is the same substance as that of which the mold a resinous substance incorporated with siliis made, the latter isnot thereby soiled. cious marl.

My improved product is infusible, non-h In witness whereof I have hereunto set my groscopic, non-adhesive, and of lower specific hand in the presence of two witnesses.

5 gravity than water. ERNST BRUHL. Having thus described my invention,- I Witnesses:

' cla1m WOLDEMAR HAUPT,

The herein-described product consisting of I-IENnY HAsPER. 

